Helicopter



March 21, 1950 P. M. LEWIS 2,501,227

HELICOPTER Filed oet. 24, 1944 s sheets-sheet 1 I N VEN To@ Fo@ THE PTR/v1 Arroz/vers March 2l, 1950 P M, LEWIS 2,501,227

z 125 124 35 122 121 114 l b' 1z0 33 134 l"-80 95a 96a. '95@ Br WEC/1 fsrie CHAR/as P. M. LEWIS March 2l, 1950 HELICOPTER Filed Oct. 24, 1944 3 Sheets-Sheet 5 Patented Mar. 2l, 1950 HELICOPTER Paul M. Lewis, Los Angeles, Calif., assigner to Peninsular Metal Products Corporation, Detroit, Mich., a corporation of Michigan Application October 24, 1944, Serial No. 560,117

.5 Claims.

This invention relates to aeronautical apparatus, and more particularly to the helicopter type of aircraft.

A general `object of the invention is to provide aircraft of the helicopter type which shall Abe useful for civilian oper-ation, shall be possessed of a large degree of safety, shall have good stabilizing qualities and shall have good maneuvera-bility.

It is a further object of the invention to provide transversely spaced rotors possessing both lifting and propelling functions which are arranged upon the body or fuselage of the aircraft in a relatively compact relationship, whereby to confine the overall spread of the aircraft within modest limits. It is also an object to provide in such construction and arrangement adequate stabilizing characteristics.

I-t is a further object of the invention to employ rotors possessing structural characteristics similar to conventional airplane propeller-s, but structurally modified to provide adequate lifting surfaces for any `given craft, as well as adeouate propelling properties.

Another object of the invention is to provide a helicopter capable of being maneuvered solely by bodily adjustment of the positions of the rotors and adjustment of the positions of the blades of the rotors.

A further object is to provide la tail rotor so mounted and constructed as to impart adequate tail stabilization and to provide for trimming the ship.

It is a further object of the invention to provide a helicopter type Ioi' aircraft which may land upon water as well as upon the surface of the ground.

Important features of the invention are lfound in the employment of -a pair of opposed power rotors which are in general horizontally disposed but are mounted upon vertical axes which may be tipped to change the angle of attack so that the r-otors are readily adjustable for substantially vertical ascent and descent, and, upon ascent, are readily adjustable for relatively high rates of forward speed. Such axes may also be so adjustable as to provide straight line movement rearward as may be necessary `in `connection with parking the aircraft in a small area. An additional feature of the invention is found in the provision of housings laterally disposed at the opposite sides of the aircraft, in which housings means are mounted providing the vertical axes of the rotors, means being included therein for driving vertical shafts adapted to actuate the f rotors. According to one form of the invention, these housings may include separate motors for the respective rotors, In another form fof the invention one Vor more motors may be provided within the fuselage or body of the aircraft for actuation of the rotors. In both forms, it is pre-- ferred that the rotors and their engines be interconnected whereby an important new feature of the invention is attained which consists in synchronizing the rotors so that opposed rotors may be arraged relatively closely to each other with their blades working in partially overlapping paths, the relative dispositions of the blades being such that the blades of two cooperating rotors are interspaced and travel in alternating succession through the common portion of their paths without interference. For stabilization purposes, the rotors travel in opposite directions so that blades moving through the overlapping or common portions of their `respective paths move in the same direction. Preferably, the blades, when traveling in the outermost portions of their respective paths move rearward to accomplish increased stabilization and increased forward speed, the blades being so pitched as to attain that end. In addition to the two cooperating rotors mentioned, which constitute the power rotors and are positioned forwardly of the aircraft, a feature of the invention is employing at the tail of the aircraft a single rotor also operating in a substantially 'horizontal plane for the purpose of stabilizing the tail of the craft. lt is a further feature of the invention for the purpose of enhancing stabilization, to cant the vertical aXes of the power rotors toward each other whereby to lower the overlapping portions of the paths of the power rotors and to raise the outermost portions of `said paths, and it is a further feature to improve stabilization by .canting the axis of the tail stabilizing rotor so that the forward portion of the path thereof is lowered somewhat. Other features of the invention are found in specific means for adjusting the positions of the axes of the power rotors, means for adjusting the longitudinal axes of the blades of the rotors to maneuver the aircraft as required and connected driving means between the various rotors.

A further Vfeature is found `in rendering the lower portion of the fuselage, and the lower portions -of the housings carrying the driving means for the power rotors, water-tight, so that the craft may land upon water. For the purpose of landing the craft upon land when desired, landing 'Wheels are provided in downwardly opening water-tight recesses in the lower extremities of the housings, tail landing means or skid means being similarly mounted upon the tail of the fuselage.

Other objects and features of the invention willbe apparent to those skilled in the art to which this invention pertains, as will become evident upon reference to the accompanying ldrawings wherein certain embodiments of the invention-are disclosed merely for :the purpose 4of illustration.

In these drawings,

Fig. 1 is a side elevation of an assembled helicopter constructed according to the present invention;

Fig. 2 is a plan view of the construction shown in Fig. l;

Fig. 3 is a front elevation of the structure shown in Figs. l and 2;

Fig. 3a shows relative blade positions when tipped in forward flight and viewed from the line 3a 3a of Fig. 3;

Fig. 4 is a fragmentary enlarged vertical transverse section taken approximately from the line 4 4 of Fig. 2;

Fig. 5 is an enlarged vertical sectional detail taken on the irregular line 5 5 of Fig. 4;

Fig. 6 is a vertical sectional detail taken on the irregular line 6 6 of Fig. 4;

Fig. 7 is a vertical detail taken approximately on the line 'I 'I of Fig. 2;

Fig. 8 is an enlarged elevational detail taken as indicated by the line 8 8 of Fig. 4, showing the means and indicating the manner of rocking the vertical housings carrying the power rotors whereby to adjust the vertical axes of these rotors;

Fig. 9 is an elevational detail taken from the line 8 9 of Fig. 8, showing cable actuating means for simultaneously adjusting the axes of rotation of the power rotors and adjusting the horizontal axes of the blades of the rear stabilizing rotor;

Fig. 10 is chiefly an elevational detail of steering mechanism disposed in the cockpit of the aircraft, gear trains being shown through which the power rotors and clutches therefor are controlled;

Fig. 11 is a vertical sectional detail taken on the line I I I I of Fig. 10, showing principally the means for controlling the pitch of the blades of the respective power rotors; and

Fig. l2 is an end elevation corresponding with that of Fig. 3 and showing a modified form wherein a single engine for the two power rotors is enclosed in the fuselage of the aircraft.

In the form of helicopter construction of Figs. 1 to 11, inclusive, a fuselage I5 or conventional construction is shown as being provided at its forward portion with a suitable removable transparent hood I6 normally enclosing a cockpit in which a seat II for a pilot and passengers is provided adjacent to appropriate control mechanisms hereinafter described.

Arranged laterally of the forward portion of the fuselage I5 are two power rotors I8 disposed in generally horizontal positions on generally vertical axes, and at the rear of the fuselage is disposed a single, preferably relatively small stabilizing rotor 28 mounted in a special tailpiece 22 of the fuselage I5.

The two rotors I8 are carried respectively in vertically extending narrow housings 24 which enclose means constituting the axes about which the rotors I8 operate. The housings 24 are rotatably carried upon transversely extending sleeves 25 which are rigidly secured to the upper portion of the fuselage I5. Obviously, any suitable additional bracing means (not shown) may be employed if necessary or desirable. The housings 24 are adapted to be rotated about an axis extending centrally of the sleeves 25, such motion ybeing permitted through the medium of telescoped sleeves 26 (Fig. 4) suitably journaled within the sleeves 25 and extensions thereof, the sleeves 26 being interconnected adjacent the upper middle portion of the cockpit by an enlarged connecting housing 21. Thus, when the 4 aircraft is at rest upon the ground, the interconnecting sleeves 25 serve to support the fuselage I5 through the medium of the housings 24. Direct ground contact is provided by ground wheels 28 disposed in water-tight downwardly directed cavities 28a in the lower portions of the housings 24, and by any similarly arranged skid or ground wheel 29 provided in the tail of the fuselage I5. The lower portion of the fuselage I5 being watertight and the lower portions of the housings 24 being water-tight, the craft may land and float upon water.

In the form of construction of Figs. 1 to 4, an engine 30 is mounted in each of the housings 24 and provided with an upright drive shaft 32 (Fig. 4) provided with a bevel drive gear 33 meshing with a bevel gear S4 carried on a hollow shaft 35 journaled in any desired manner within the sleeve 26. The bevel gear 34 in turn meshes with a bevel gear 36 on the lower end of a hollow shaft 38 secured to a hub 40 which receives journaled spindles 4I of blades 42 constituting part of the respective rotors I8. The hollow shaft 38 is mounted in any appropriate bearings 44 carried within the respective housing 24. In this manner an engine 3D operating from its shaft 32 through the gear train 33, 34 and 36 and through the hollow shaft 38 and hub 40 serves to rotate the respective rotor I8.

Through the medium of the hollow drive shaft 35 carrying the bevel gear 34 of each engine 30, the two engines 30 are maintained in synchronized relation by reason of bevel gears 45 carried on their opposite ends and disposed within the connecting housing 2'I. In this form of the invention the bevel gears 45 mesh with a central gear 46 carried on a shaft 48 mounted in any suitable bearings (not shown) and extending into the tail of the fuselage I5 to drive the stabilizing rotor 20, as indicated in Figs. 6 and '7. This is accomplished through the medium of a bevel gear 50 carried on the rear end of the shaft 48 and meshing with a bevel gear 5I fixed on the lower end of a hollow drive shaft 52 whose upper i end is secured to a hub 54 receiving suitably journaled adjustable spindles 55 of blades 56 constituting the rear stabilizing rotor 2U. The hollow drive shaft 52 is journaled in the tailpiece I22 at the rear of the fuselage I5 in any appropriate manner not indicated.

By reason of the interconnection of the two rotors I8 and the two motors 30 through the hollow drive shafts 25, the bevel gears 34 and 45 and the central bevel gear 46, the two engines 3U and the two power rotors I8 are properly synchronized so that the blades 42 of the rotors I8 are always properly disposed in interspaced relationship as they pass through the common or overlapping portions of their respective paths. Also, as will be noted by reference to Figs. 3 and 4, the axes of the power rotors I8 are inclined toward each other for the purpose of producing further stabilization of the craft. This is by reason of the fact that the propeller blades 42, as indicated especially in Fig. 1, are tipped upward as they extend outward somewhat after the fashion of standard airplane wing disposition. It is desired that the blades 42 in traveling through the overlapping portion of their paths move in the same plane to avoid undue air agitation. By tipping the axes as indicated, the blades are thus brought into the same horizontal plane as they pass above the fuselage I5, this being best indcated in Fig. 3. It will also be noted that the axis of the stabilizing rotor 20 on the tail of the fuseasomar lage- I is tipped forward. This serves. to stabilize the fuselage and at the same time to add tothe propelling power.I

In order to impart a desirable and convenient forced air circulation over the engines 30 through the housings. 2li, upwardly directed louvers; 60 are provided in the upper portions of the opposing sides of the housings 24, so that the` tips of the blades 112 of the opposite rotors I8, which travel at high rates of speeds as they pass above,- andf adjacent the respective louvers 60, will tend to. force air currents at high rates of Speed down, through the louvers and into the housings 24. At positions rearward of the engines 3.0, rearwardly directed nozzles 6I are provided on the housings 24, whereby a partial vacuum effect aids air circulation. Air circulation is further produced byr projectingv the engine exhaust pipe 62- of, the. respective engine part way into eachY nozzle 6| thereby effecting ejector action.y

For the purpose of tipping the housings 21|` thereby to tip forward theA axes about whichthe rotors IS rotate, the housing member 2.1. which connects. the sleeves 26, that are in turn fixed to. the housings E.'24, is adapted to be oscillated through various positions, as indicated in Fig. 8

For this purpose, the housing member 21 is provided with a depending hollow leg 65` (Figs. 4:,v 6` and 8), on one of whose outer faces at the lower end is. provided a pocket or guide means. 661 which slidably receives, a vertically disposed actuating finger 6l pivotally connected at 61a4 to a grip device 68 holding the ends of a cable 'I0A which passes around spaced pulleys 1|. The movement of the grip 68, is guided in an elongated channel member l2. The cable 'I0 and the.y grip 68 are actuated through the medium of an endless Qable lwhich passes around a second groove in` one of the pulleys '|I and thence around one of a group of pulleys 14, to an actuating pulley 1,5secured to a` control wheel ltpivotally mounted upon a shaft 'I8 secured in the adjacent side wall of the fuselage I5V and providedv with a, crank handle 'I9 for other control purposes subsequently to be described.

For the purpose of controlling a driving connectionl of the engines 30- with their respective rotors I8, each. engine is provided with a clutch, such as generally indicated at 80, which is connected with. the drive shaft 32,` The `clutch 80 has. a looped yoke 82 (Figs/1 and 5) operatively connected, thereto, the yoke 82 being adapted to belifted by the elevated portion of a cam membery |33 which. cooperates with an engaging cam part 84. on the yoke 82 and,v is rotatable forI adjustmentA purposethrough the medium of al hollow shaft 85 mounted within the hollow shaft4 35` as through the medium of suitable.bearings 8 6. One shaft 85 extends into the connectinghousingl 21, and has xed thereon a bevel gear 81. The bevel gear 81 is engaged by a cooperating bevel gear 88 which is adapted to be actuated through the medium of a sectional control shaft 90 provided vvith suitable universal joints 92, the sec,- tionalv shaft 90 extending into the lower portion o f thedepending leg 65 and being there provided with a worm gear 93 which meshes with a worm 94 on a horizontally disposed shaft 95. The sectional shaft 90 and the shaft 95 are suitably positioned by appropriate bearings not shown. In,` order to4 permit oscillation of the depending leg,

65 through its various movements, as indicated in Fig.y 8, the4 shaft 95 also is sectional and is proq vided with suitable universal joints. 96 and with atelescopic joint 9'|-so that as the leg 65 isswung from one position to another to rock the sleeve 25 and the axis of the respective rotor |8, the unil-1 versal joints may flex and the corresponding portions -of the shaft 95 may telescope. The telescopic portions. will, for example, be square in order to provide for rotary drive. rIhe shaft 95 extends forward to the pilots position in the cockpit where its forward end has a bevel gear 98 (Fig. 10) secured thereto, the gear 98 meshing with a, double bevel gear 99, one side of which. meshes with a segment gear |00 fixedly secured to a rotatable shaft |02` extending upwardly to the pilots operating level where it is provided with a handle |03 constituting a portion of a multiple maneuvering control device generally indicated at |05.

The above description of a clutch actuatingI mechanism as applied to one engine 30, also applies to the same construction of clutch mechanism actuating the other engine 30, the parts therefor being indicated by the same referenceV numerals with the suffix a. In Fig. 4, the shaft a. islocated behind the shaft 90, and in Fig-` 6, the shafts 90 and 90a are located behind othershafts presently to be described.

Located within each hollow drive shaft B5 which controls the respective clutch 80, is a shaft ||0 journaled in bearings I I, the shaft carrying a gear I I2 meshing with a rack bar l Ill which extends upward within the hollow drive shaft 38 for the respective rotor I8 and is operatedly connected to impart rotary adjusting movement to a shaft I I5 mounted in a bearing l It (Fig. 5) and having above the bearing ||6 a gear Ill which meshes With segmental gears I I8 on both the ad jacent ends of the spindles 4I of the blades 42 constituting the rotor l 8. As shown in Fig. 5, the rack bar H4 is provided with a head |25 which is connected by a freely rotating bearing I-2| with a sleeve |22 having an internal spiral thread |24- meshing with an external spiral thread |25 on the shaft H5. The rack bar llt is held in engagement with the gear I I2 and against rotation with the hollow drive shaft 38 by any suitable bracket means (not shown) connected with the respective housing 24. As the shaft I Ill and the gear H2 are rotated, vertical movement of the rack ||4 causes corresponding rotation of the shaft I |5 by reason of the threadsy |24 and |25 whereby to ad'- just the blades 42 about their longitudinal axes and thereby change the pitch of both blades si-y multaneously.

Actuation of the shaft I I0 by the pilot from thev control mechanism |05 in the cockpit is obtained through the medium of a bevel gear |30 fixed on the end ofthe shaft H0. in the connecting housing 21, the gear |30 meshing with a bevel gear |32 mounted on a suitably positioned jointed shaft |84 having universal joints. |35. The shaft |34 dependsA within the leg 65 of they housing 2 7 and carries on its lower end a worm gear 30 meshing. with a worm |37 on a rotary control shaft |38 like the shafts and 95a. The shaft |38 possesses universal jointsv |30 and a telescopic connection |40., and by these means is operatively connected by bevell gears |42 with a bevel gear |43 on the.4

lower end of a shaft |44 which extends upwardly through a hollow post M5` of the control device Here,I the.L gear |4311 is securedA onl the lower end; ofa, hollow shaft |50 through which the shaft |44 ex atome? tends, the .shaft carrying on its upper end a control wheel |52 operable by the pilot.

Means are also provided for adjusting the pitch of the blades 56 of the rear stabilizing rotor 20. This is accomplished by means shown in Fig. 7 which is substantially the same as that shown in Figs. 4 and 5 for adjusting the pitch of the blades 42 of the rotors I8. In Fig. 7, a gear I |2a mounted on a shaft |60 engages a rack ||4a which serves to impart rotary motion to a shaft ||5a disposed in the hollow drive shaft 52 and carrying a bevel gear l Ila meshing with sector gears H811 secured to the spindles 55 of the blades 56 for oscillating adjustment of the blades 56 about their longitudinal axes. As in the form of Fig. 5, the rack EMG. has a freely rotatable connection |2511 with a sleeve |22a carrying an internal helical thread engaged with an external helical thread |25a on the shaft ||5a. Thus, as the gear |i2a is rotated to impart longitudinal motion to the rack ||4a and the sleeve |22a, the interengaging of the helical threads causes reciprocal motion of the sleeve |22a to impart rotary motion to the shaft ||5a and correspondingly rotate the blades 56. The shaft |60 and the gear i |2a are rotated through the medium of a cable |62 and a pulley |64 which receives the cable E52. These parts are positioned by journaling the ends of the shaft |60 in adjacent mountings carried in the tailpiece 22 to which may be connected a bracket I6 5 which serves to retain the rack Ma in engagement with the gear |2a and also to prevent tendency of the rack |4a to rotate. The -cable |82 leads from the tail of the ship about a series of guide pulleys |65 to the front of the ship whence it passes around suitable members of the series of pulleys 14 (Figs. 8 and 9) and thence to a pulley ISE; on the shaft 'I8 carrying the crank handle 19. Thus, by operation of the handle 19, the cable |62 is actuated for proper movement of the gear l |2a and the .p

rack I |4a to obtain the desired adjustment of the blades 56 of the rear rotor 20.

In the construction illustrated in Fig. 12, a single motor 30a is employed instead of the two motors 30 of the form of Figs. 1 to 11. Here, the motor 30a is appropriately mounted in the fuse-f lage |5 and provided with a driven gear 33a that meshes with the central gear 4B, whereby the central gear 4B drives the hollow drive shafts 35 through the medium of the gears 45 and thus drives the rotors I8 through their hollow drive shafts 33 by way of the bevel gears 34 and 36. In these respects, the construction may be identical with that of the other form, except that clutch actuating means for the motor 30d will not be required to extend out to the housings 24, and the housings 24 obviously will not be provided with power plants. However, the same means used in the other form for changing the pitch of the blades 42 of the rotors |8 maybe employed.

Operation In operating a helicopter constructed according to the improvements of the present invention, the engines 30 are started in any desired manner, the clutches (Figs. 4 and 5) having been first disengaged. Clutch disengagement is accomplished by the lifting cams 83 operating upon the clutch controlling yokes 82 through the medium of the hollow shafts 85 and the bevel gears 81 (Figs. 4 and 6), the bevel gears 81 being actuated through the bevel gears B8 and 88a, the jointed shafts and 90a, the sectional shafts 95 and a, and the gears 98, 98a and 99, 99a from 8 thecontrols |03 and |03a of the control mechaJ nism |05, shown in Fig. 10.

The engines 30 having been properly warmed, the clutches 80 are engaged by actuation of the r, controls |03 and |03@ whereby rotation of the blades 42 of the power rotors |8 is effected in the direction of the arrows oi Fig. 2. The pitch of the blades 42 will have been adjusted to a suitable position, such as that indicated in Fig. 3, for ascent of the ship, the axes of the rotors I8 will have been disposed in vertical position, and the blades-56 of the rear rotor 20 will have been adjusted about their longitudinal axes for proper stabilization of the ship during ascent,

Ascent to a proper height having been effected, forward motion is best accomplished by tipping the axes of the rotors l forward, whereby to obtain a proper angle of attack by the blades 42. This is accomplished by tipping the housings 24 .so that their upper ends move forward, the motion being accomplished by rotating the sleeves by rocking or oscillating the lower end of the Yleg B5 of the central housing 21 by adjustment of the cable 'Hl and the actuating nger 61 through the medium of the cable 'i3 which leads from one of the pulleys '1| around pulleys of the unit 'i4 to the pulley 'I5 which is controlled by the hand wheel 1G adjacent the pilots position in the cockpit. When the blades 42 of the rotors i8 are properly adjusted about their longitudinal axes for forward flight, the tipping of the rotors i8 bodily forward causes the blades which are moving forward in the common or overlapping portion of the paths of the rotors to move in a substantially horizontal plane. The same adjustment causes the blades to assume a steeper position as they rotate into the outermost portions of their paths, as a result of which the greater angle of attack produces greater propelling action. In other words, the flattened blades passing through the common portion of the paths of the rotors tend to slip forward through the air, whereas the blades moving rearward in the outermost portions of their paths attack the air positively at a steep angle to obtain maximum propelling effect as indicated in Fig. 3a. By reason of the interconnection of the rear rotor 20 by means of the shaft 48 and its connection with the central gear 46, proper stabilization of the tail of the ship is obtained. The permanent tipping forward of the axis of the rotor 20, as indicated in Fig. 1, improves its stabilization effect and at the same time permits at least a limited amount of propulsive work.

Maneuverability of the ship is readily effected by adjustment of the various blades 42 of the power rotors I8 and the blades 56 of the stabilizing rotor 2|) about their longitudinal axes. For example, a turn to the right may be accomplished when the axes oi' the rotors IS are tipped forward in propelling position by leaving the blades of the left rotor in driving position and rotating the blades of the right rotor about their longitudinal axes so as to reduce the driving effect of the right rotor |8. Such adjustment of the various blades of the righthand rotor I8 about their longitudinal axes is accomplished by actuation of the shaft ||0 (Fig. 4) through the medium of the bevel gears |36 and |32, the jointed shaft |34 and sectional shaft |30 by the pilot from the cockpit through the medium of the hand ,wheel |46 (Fig. 11), the shaft |44 and the gears I 42 and |43. Rotation of the shaft III), as previously described, causes the gear H2 to impart vertical motion to the rack II fl (Figs. 4 and 5) whereby bodily vertical movement of the sleeve |22 (Fig. 5) imparts rotary adjustment to the shaft II5, the bevel gear III and the sector gear I I 8 through the influence of the interengaging helical threads |24 and |25 in the sleeve |22 in the shaft II5. The rotary joint at I2! is such as to permit free rotation of the sleeve |22 upon the head |20 of the rack bar II4 while at the same time imparting vertical movement to the sleeve |22 corresponding with that of the rack bar II4.

For the purpose of turning in the opposite direction, the pilot will turn the wheel |46 (Fig. 1l) to restore the blades of the right rotor I8 to driving position, the blades of the left rotor I8 then being adjusted through the medium of the hand wheel |52 to reduce their driving effort. Similarly, the ship may be trimmed by adjusting the blades 56 of the rear rotor 2D about their vertical axes through the medium of the mechanism shown in Fig. 7.

For the purpose of vertical descent, the leg 65 of the housing 2'I (Figs. 4 and 8) is restored to an intermediate position so that only lifting eiiects are obtained, thereby allowing the ship to settle. It is possible, in parking the ship, to move the sarne rearward to some extent, by tipping the leg 65 in the opposite direction so as to tip the upper ends of the housings 24 and the upper end of the axes of the rotors I8 rearward, this also being accomplished by the pilot from the cockpit through the medium of the hand wheel 'I6 (Figs. 8 and 9) and the cable 13.

As has been previously indicated, good cooling effects are obtained by the action of the tips of the propellers as they move through the common portion of their paths above the fuselage I5 whereby air is forced at high speed down through the opposite louvers 6U in the opposing sides of the housings 24, circulation continuing past the motors 30 within the housings 24 and thence outward through the nozzles 6I, s-uch venting of cool air being facilitated by the ejector effect of the exhaust from the engines through exhaust pipe 62.

By reason of the permanent interconnection between the power rotors I 8, the ship may be handled through one engine in the event that the other engine fails, this being accomplished merely by throwing out the clutch of the engine which has failed. Under such circumstances, the rotor whose engine has failed is driven from the other engine by Way of the hollow drive shafts 3'5, the central bevel gear 46 and bevel gears 45 within the connecting housing 2'I.

Also, by reason of the fact that the lower portions of the housings 24 and of the fuselage I5 are water-tight, the craft may be employed for settling upon water and taking 01T therefrom as well as for land use.

In the operating the form of Fig. 12, manipulating procedures are substantially the same. In this form, as in the other form, the two power rotors I8 and the stabilizing rotor 29 are all connected by shafts and gears. In this construction, also, the housings 24 are tipped forward to change the angle of attack of the rotors I8 as the pilot desires. Mechanism substantially the same as that for the form of Figs. 1 to 11 is employed for actuating the rotors I8 and 20, and for adjusting their blades about their longitudinal axes. In this form, more than one engine may be employed, so that if one engine fails, it may be disconnected by throwing out its clutch and all rotors I8 and 29 driven by .a single engine.

It will become apparent to those skilled in the art that many modifications of the generic invention herein disclosed may be made without departing from the spirit of the invention. Therefore, it is intended that all modifications shall be protected as fall within the scope of the appended claims.

I claim as my invention:

l. In combination in a helicopter: an elongated body having a longitudinal axis; spaced rotors disposed on substantially vertical axes at the opposite sides of said body, said rotors having blades normally in substantially horizontal planes; hollow means extending laterally from said body to support said rotors; housing means connected with the outer ends of said hollow supporting means and directly supporting said rotors; means in said housing means to drive said rotors; clutch means in said housing means to engage and actuate said drive means; clutch operating means extending from said body through said hollow supporting means to control said clutch means; 'means on the inner ends of said blades to rotate the same about their axes and change their pitch; and rotary drive means disposed on the axes of said rotors to actuate said means for changing pitch.

2. A combination as in claim 1 wherein said rotary drive means includes telescopic, threaded drive connections.

3. A combination as in claim 1 wherein said K means on the inner ends of said blades are gears,

and said rotary drive means include means to engage and actuate said gears.

4. A combination as in claim 1 wherein said rotary drive means include rack and gear drives.

5. In combination in a helicopter: an elongated body having a longitudinal axis; spaced rotors disposed on substantially vertical axes at the opposite sides of said body, said rotors having blades normally in substantially horizontal planes; hollow means extending laterally fromv said body to support said rotors; housing means connected with the outer ends of said hollow supporting means and directly supporting said rotors; motors mounted in said housings to drive said rotors respectively; vent means in said housings; and upwardly directed louver means in said housings to receive descending air currents from said rotor blades, the tips of the blades of each rotor being arranged to pass close to said louver means of the opposite housing.

PAUL M. LEWIS.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,838,327 Salisbury et al Dec. 29, 1931 1,849,766 McGuire Mar. l5, 1932 1,878,955 Mantell Sept. 20, 1932 1,892,036 Campens Dec. 27, 1932 2,982,375 Boettner June 1, 1937 2,186,992 Reinhard et al. Jan. 16, 1940 2,321,572 Campbell June 15, 1943 2,375,592 Smith May 8, 1945 FOREIGN PATENTS Number Country Date 317,059 Great Britain Feb. 9, 1931 502,335 France Feb. 19, 1920 

